Steam-engine.



PATENTED JAN. 20, 1903.

C. LEAN.

STEAM ENGINE.

APPLIOATION FILED 4m. 22, 1901.

9 SHEETS-SHEET 1.

H0 MODEL.

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PATENTED JAN. 20, 1903. G. LEAN.

STEAM ENGINE.

APPLICATION FILED APR. 22, 1901.

9 SHEETBSHEET 2.

N0 MODEL.

n4: Nonms wzrzas cu. Puoroumcq WASHINGTON. n. c.

PATENTED JAN. 20, 1903.

G. LEAN.v

STEAM ENGINE.

APPLICATION 21mm APR. 22, 1901.

9 SHEETS-SHEET 3.

H0 MODEL.

PATENTED JAN. 20, 1903.

c. L AN, STEAM ENGINE.

APPLICATION FILED APR. 22, 1901.

9 SHEETSBHEET 4.

- N0 MODEL.

No. 718,715. PATENTED JAN. 20, 1903. G. LEAN.

STEAM ENGINE.

I APPLICATION FILED APR. 22, 1901.

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PATENTED JAN 20', 1903. U. LEAN.

STEAM ENGINE.

APPLIGATION FILED APR. 22, 1901.

9 SHEETS-SHEET 7.

N0 MODEL.

PATBNTED JAN. 20, 1993.

C. LEAN.

STEAM ENGINE.

APPLIOATIONIILED APR. 22, 1901.

9 SHEETS-SHEET 8.

K0 MODEL.

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No. 718,715. PATENTED JAN. 20, 1903.

STEAM ENGINE.

APPLICATION TILED APR. 22, 1901.

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CLEMENT LEAN, OF NEl/V CROSS, LONDON, ENGLAND.

STEAM-ENGINE.

SPECIFICATION forming part of Letters Patent No. 718,715, dated January 20, 1903.

Application filed April 22, 1901 Serial No. 56,971. (No model.)

T at whont it vncty concern.-

Be it known that I, CLEMENT LEAN, a subject of the King of Great Britain, residing at 99 Jerningham road, New Cross, in the count-y of London, England, have invented a new and useful Improvement in Steam-Engines, of which the following is a specification.

This invention relates to the valves and valve-gear of steam-engines, compressed-air engines, and the like, and has for its object the provision of means whereby the cut off of the motive fluid may take place suddenly and certainly at high as well as at low speeds of running.

According to my invention the means for actuating the cut-off mechanism are provided witha member which is always acted upon by the pressure at one of the sides of the piston.

According to'my invention I provide separate cut-off valves, and I employ supplementary cylinders both to open and to close these valves, detent mechanism being employed to normally hold the cut-off valves in the closed or open position, said detent mechanism being released at the times for cut-oft by means regulated by a governor.

According to my invention I employ the main admission and exhaust valves to admit steam to and exhaust the same from the supplementary cylinders which operate the cutoff valves. To this end ports are arranged not only between the main admission and exhaust valves and the main cylinder end spaces, but also between these valves and the supplementary cylinders.

In order that my invention may be better understood, I will now proceed to describe an embodiment of the same, reference being had to the accompanying drawings, which illustrate an engine of the Corliss type provided with valves and valve-gear according to my invention.

In said drawings, Figure 1 is a side elevation of the cylinder end of the engine. Fig.

,1 is a diagrammatic side elevation of the crank-shaft end of the engine. Fig. 2 is a plan, and Fig. 3 is an end view, of the same, parts being omitted for the sake of clearness. Fig. 4 is a part-sectional side elevation on the line IV IV, Fig. 2. Fig. 5 is a sectional end elevation on the line V V, Fig. 2, of the in plan.

main cylinder-casting and valve-seats. Fig. 6 is a side elevation of the cylinders and piston-rod for actuating the cut-off valves. Fig. 7 is a part-sectional side elevation of said cylinders, the central part of the rod being shown Fig. Sis a front elevation of the trip or detent mechanism. Fig. 9 is a plan of the same. Fig. 10 is a sectional elevation of a modified form of cylinder and piston for actuating the cut-ofi valves.

1, Figs. 1 and 2, is the outside casing of the engine-cylinder 2, Fig. 4, containing the piston 3, Fig. 4. This piston-rod 4, Fig. 4, is connected in the usual way with a cross-head guided in the trunk 5, Figs. 1 and 2, and connected by the connecting-rod 6, Fig. 1, with the crank-disk. (Indicated by the dotted line 7, Fig.1) The crank-disk is mounted on the crank -shaft 8, which revolves in suitable bearings 9 9, only one of which is shown in the drawings. lhe rim of the fiy-wheel is indicated by the dotted line 10, and the circle 11 indicates the outer casing of a suitable shaft-governor. The two admission-valves 12 13, Fig. 4, are arranged above the cylinder at its two ends, and the two exhaustvalves 14 15 are similarly situated below the cylinder, and all four valves are preferably actuated by a single eccentric-rod 16, Figs. 1 and 2, from a wrist-plate 17. Each of the shafts 18 18 of these four valves is provided with an arm 19, which is connected by means of an adjustable connecting-rod 20 with said wrist-plate. The eccentric-rod 16 is actuated by an eccentric fixed on the crank-shaft 8 and operates a pivoted lever 21, which drives the Wrist-plate through the connecting-rod 22. The admission-valves are arranged to open at approximately the beginning of alternate strokes and to close at any convenient period of the back stroke, the closure being late enough to allow a sufficiently wide range of cut-off.

In order to cut oft the steam at a point in the piston-stroke varying with the load on the engine, I provide a separate pair of valves 23 24, Fig. 4, which are connected together, as hereinafter described, and are adapted to close the admission-ports 25 26 at the required times for cut-off. The cut-0E valves 23 24 are adapted to be actuated by two pistons 27 28, Fig. 7, which are arranged in separate cylinders 29 30, Figs. 1, 2, 3, 6, and 7, and are connected together by a connectingrod 31, Figs. 1, 2, 6, 7, 8, and 9, preferably formed in two or more parts connected to gether. The end spaces 32 33, Fig. 7, of the cylinders 29 30, respectively, (hereinafter termed cut-off cylinders,) are permanently in direct communication with the two end spaces 31 34 35, Fig. 4, respectively, of the main cylinder 2 through the tubings 36 37, Figs. 1, 2, 3, 6, and 7, respectively, which may be of copper or other suitable material. These tubings provide a closed passage between two ports 38, (one of which is shown in Fig. 5,) and the cut-off-cylinder end spaces, said ports 38 opening into the two end spaces 34 35 of the main cylinder.

The two pistons 27 28 actuate the cut-01f valves 23 24 through the connecting-rod 31, which is slidingly supported in a bearing 39, Figs. 1, 2, formed on the bearing 40 of the wrist-plate 17. Said connecting-rod when operated drives the cutoff valves 23 24 through the adjustable connecting-rods 41, 42, Figs. 1 and 2, which are attached to the ends of the arms 43 44, fixed on the shafts of the valves 23 24, respectively.

\Vhen steam is admitted alternately to the two end spaces 34 35 of the main cylinder, steam is admitted alternately to the two end spaces 32 33, respectively, of the cut-off cylinders 29 30. The cylinder end spaces 68 7O serve to cushion the pistons and parts connected therewith, the air being able to escape to the atmosphere through the passages 69 71 alone.

In Fig. a modified form of cut-off cylinder and cushioning device is shown. The piston 72 is provided with a piston-rod 73, which is connected by a rod with a similar piston in a similar cylinder by similar connections to those shown in Figs. 6 and 7. The piston 72 is also provided with a trunk 74, so that the area of the piston exposed to pressures in the end space 75 is much less than the area exposed to pressures in the end space 76. The end space 75 is connected by the tubing 77 with one of the main-cylinder end spaces, this tubing 77 corresponding to the tubing 36, previouslydescribed. The cylinder-wall is provided with by-pass ports 78 78, whereby the steam is able to pass into the cylinder end space 76 when the ports are put into communication with the cylinder end space 75.

The pistons 27 28 are prevented from moving before cut-off is to occur by means of any suitable detent mechanism, such as that shown in Figs. 1, 2, 8, and 9. The pivoted detents 45 46 are adapted to engage alternately the two ends 47 48, respectively, of the block 49, which is rigidly mounted on the extension of the connecting-rod 31, said extension being slidingly guided in the bearings 51 52, formed in the lower portion of the standards 53 54, cast integral with the support 55, which is bolted on the side of the cylinder-trunk 5, as shown in Figs. 1 and 2. The pivoted detents 45 46 are provided with arms 56 57, connected together at their outer ends by means of a spring 58, which tends to depress the ends of the detents 45 46. The arms 56 57 are provided with faces 59 60, Fig. 8, against which the pin 61, carried by the rod 62, is adapted to strike at the times of cut-off. Said rod 62 is guided in bearings 63 64, formed in the upper portion of the standards 53 54, respectively, and is reciprocated by the rod 65, pivoted at the end of the lever 66, which is reciprocated by the eccentric-rod 67 from the eccentric of a shaft-governor of any suitable type, the casing of which is indicated by the circle 11.

The cycle of events which take place is as follows: Supposing the piston 3 to be commencing the outstroke and to be in the position shown in Fig. 4, steam is admitted to the front end space 35 of the cylinder 1 through the admission-valve 13,which hasjust opened, and through the cut-off valve 24, which is full open, the pistons 27 and 28 being in the position shown in Fig. 7. The exhaust-valve is closed, and steam enters the end space 33 of the cut-off cylinder through the tubing 37. During the period of admission of steam to the end space the end space 34 is open to exhaust on account of the exhaust-valve 14 being open and both the admission-valve 12 and the cut-olf valve 23 being closed, and consequently the end space 32 of the cut-off cylinder 29 is also open to exhaust through the tubing 36 and the port 38, Fig. 5. The rod 31 is, however, prevented from moving under the pressure of the steam in the piston 28 by means of the detent 46, which is in its position of engagement with the end 47 of the block 49 on the extension of said rod. When cut-off is to occur in the main cylinder 1, the pin 61 strikes against the face on the arm 57 of the detent 46 and trips said detent, so that the steam-pressure on the piston drives the rod 31 suddenly forward, thereby suddenly closing the cut-off valve 24 and effecting cut-off in the main cylinder. The cut-off valve 23 is opened by this movement, and the detent 45 drops down at the end 48 of the block into the position shown in Fig. 8. The cushioning of the rod 31 and the parts actuated thereby when cut-0E cylinders, as illustrated in Figs. 6 and 7, are employed is offected by the pressure of the air which is compressed in the end space 68 of the cylinder 30 by the piston 28, said end space being in communication with the atmosphere only through the small passage 69, said passage being arranged at a suitable distance from the cylinder end, so that the cylinder end space forms a closed cushioning-chamber when the orifice of the passage is blocked by the piston, the arrangement being such that the piston does not move far enough toward the cylinder end to allow communication between the atmosphere and cylinder end space 33 to be set up through the passage 69. When IIO cut-off cylinders of the construction illustrated in Fig. 10 are employed, the cushioning is effected by the pressure of the steam in the end space 76 after the ports 78 78 have placed this end space in communication with the endspace 75. If the piston moves past these ports to the position indicated in dotted lines, the steam in the end space is compressed in the closed space formed between the piston and the cylinder end. By this arrangement the cushioning is very sudden, and the cushioning pressures depend on the pressure of the steam employed. It is to be understood, however, that I can employ any other suitable means to cushion the cut-off mechanism after the detents have been tripped. time after cut-off has occurred the admissionvalve 13 closes, and at approximately the end of the outstroke the exhaust-valve 15 opens, the exhaust-valve 14.- closes, and the admission-valve 12 opens. On the opening of the valve 15 the cylinder end space 33 is open to exhaust, and on the admission-valve 12opening the piston 27 in the cut-0E cylinder 29 is subjected to the steam-pressure. The rod 31 is prevented from moving by the detent 45, which engages the end 48 of the block 49, as shown in Fig. 8. When, however, cut off is to occur, the pin 61 trips the detent 45, thereby releasing the cut-oflf mechanism,

which under the pressure of the steam in the.

cylinder end space 32 promptly produces cut oif by sharply closing the cut-off valve 23. The cut-oif valve 2a is opened again by this movement, and the detent 46 drops over the end 47 of the block 49. Subsequently the admission-valve 12 closes, and at approximately the end of the instroke the exhaustvalve 14E opens, the exhaust-valve 15 closes, and the admission-valve 13 opens. On the opening of the exhaust-valve let the cylinder end space 32 is open to exhaust, and on the opening of the admission-valve 13 the piston 28 in the cut-off cylinder 80 is subjected to the steam-pressure, the rod 31, however, being prevented from moving by the detent 46. The outstroke commences and the cycle of events is repeated.

The motion of the reciprocating pin 61 may be regulated by a suitable governor of any suitable type, the function of the governor being to cause the pin to trip the detents at points in the stroke varying with the load on the engine.

I wish it to be clearly understood that the embodiment of my invention as described above with reference to the accompanying drawings is merely set forth as an example of the means for carrying out my invention.

The essence of the embodiment of my invention as illustrated in the drawings, Whatever the type of engine or valve-gear to which it is applied, consists in means for actuating the cut-off mechanism which are operated by the motive fluid and are in connection with the two end spaces of the cylinder, so that the main valves of the engine serve also as At any suitable valves for the means for actuating the cut-off mechanism.

The advantages of avalve-gear constructed according to my invention are that extra valves are not required for the distribution of motive fluid to the means for actuating the mechanism for producing cut-oif, the main admission and exhaust valves serving to effect this distribution, and, further, the motive fluid is admitted to said means before the instant at which cut-off is to occur, so that before the instant at which cut-off is to occur the means for actuating the mechanism for producing cut-0E are already subjected to the full fluid-pressure, which when said means are released from their detent mechanism will actuate the cut-off. The cut-off is consequently very sharp by the arrangement of the detent mechanism in which the engagement of the detent with the detent-block is insured simultaneously with the throwing over of the cut-oh valves, so that any'oscillations of the detent-block during the cushioning of the pistons in the supplementary cylinders have no effect on the engagement of the detents, as this engagement is insured as soon as the detent has fallen over the edge of the detent-block, and this may be arranged to occur before or actually during the moment of complete cut-off.

I claim- 1. The combination at each end of the working cylinder of a steam-engine having a piston working therein, of a valve or valves for the admission of steam to and the exhaust of steam from the cylinder, a separate cut-01f valve, a supplementary cylinder, a piston working therein which is adapted to close the cut-off valve at the time for cut-off, ports be- ICO tween said admission and exhaust valve or v valves and said working and supplementary cylinders, said ports being so arranged that when said admission and exhaust valve or valves are operated, steam is admitted to and exhausted from, respectively, both the working and supplementary cylinders, and detent mechanism for retaining the cut-ofi valve in its open position during the period of admission, and means for releasing said detent mechanism at the time of cut-off, to enable the cut-off valve to close under the action of the steam in the supplementary cylinder, and connections between the two pistons in the supplementary cylinders to enable the operation of closing one cut-off valve to effect the opening of the other.

2. The combination with an engine-cylinder containing a working piston, of two supplementary cylinders, a piston in each of said supplementary cylinders, means connecting said pistons, a port connecting one end space of one supplementary cylinder to one end space of the engine-cylinder, and a port connecting one end space of the other supplementary cylinder to the other end space of the engine-cylinder, so that said interconnected pistons are acted upon in a differential manner by the pressures at the two sides of the working piston, two separate cut-off valves on the engine-cylinder adapted to be driven by said pistons, detent mechanism for normally maintaining said cut-off valves in the open or closed position and means for releasing said detent mechanism at the times for cut-off.

3. The combination with an engine-cylinder containing a working piston, of two supplementary cylinders, a piston in each of said supplementary cylinders, means connecting said pistons, a port connecting one end space of one supplementary cylinder to one end space of the engine-cylinder, and a port connecting one end space of the other supplementary cylinder to the other end space of the engine-cylinder, a valve at each end of the engine-cylinder adapted to admit steam to each supplementary cylinder before the time for cut-off at that end of theengine-cylinder with which said supplementary cylinder is connected, two separate cut-off valves on the engine-cylinder,means connecting said cut-01f valves with the pistons in the supplementary cylinders so that said cutoff valves are adapted to be driven by the steam-pressure on the pistons in the supplementary cylinders, detent mechanism for normally maintaining said cut-oil": valves in the open or closed position and means for releasing said detent mechanism at the times for cut-off, so that said pistons in the supplementary cylinders may operate the cut-off valves.

4. The combination with an engine-cylinder containing a working piston, of two supplementary cylinders, a piston in each of said supplementary cylinders, means connecting said pistons, a port connecting one end space of one supplementary cylinder to one end space of the engine-cylinder, and a port connecting one end space of the other supplementary cylinder to the other end space of the engine -cylinder, so that said interconnected pistons are acted upon in a differential manner by the pressure at the two sides of the working piston, two separate cut-01f valves on the engine-cylinder adapted to be driven by said pistons, detent mechanism for normally maintaining said cut-off valves in the open or closed position and means for releasing said detent mechanism at the times for cut-off, and a centrifugal governor for regulating the releasing mechanism, so that the times for cut-off are determined by said governor.

5. The combination with an engine-cylinder containing a working piston, of two supplementary cylinders, a piston in each of said supplementary cylinders, means connecting said pistons, a port connecting one end space of one supplementary cylinder to one end space of the engine-cylinder, and a port connecting one end space of the other supplementary cylinder to the other end space of the engine-cylinder, so that said interconnected pistons are acted upon in a differential manner by the pressures at the two sides of the working piston, two separate cut-01f valves on the engine-cylinder adapted to be driven by said pistons, detent mechanism for normally maintaining said cut-off valves in the open or closed position and means for releasing said detent mechanism at the times for cut-oil, and means forcushioning the pistons in the supplementary cylinders, after cut-off has occurred on the release of the detent mechanism.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

CLEMENT LEAN.

\Vitnesses:

ARTHUR V. STEPHENS, LEONARD E. HAYNES. 

